1. Field of the Invention
This invention relates to a mannequin adaptor for use with a cardiopulmonary resuscitation (CPR) mannequin for training operators in the use of an automatic or semiautomatic external defibrillator (AED). This invention is also directed to methods of modifying a CPR mannequin.
2. Description of the Prior Art
One frequent consequence of heart attacks is the development of cardiac arrest associated with a heart arrhythmia, such as ventricular fibrillation. This abnormal heart rhythm is caused by an abnormal and very fast electrical activity in the heart. During ventricular fibrillation the heart cannot pump blood effectively. Ventricular fibrillation may be treated by applying an electric shock to the patient's heart through the use of a defibrillator. Defibrillation clears the heart of the abnormal electrical activity and allows the heart's natural pacemaker areas to restore normal function. Because blood is no longer pumping effectively during ventricular fibrillation, the chances of surviving a heart attack decrease with time after the attack. Quick response to a heart attack by administering a defibrillating shock as soon as possible after the onset of ventricular fibrillation is therefore often critically important.
Increasing the number of potential defibrillator operators who are trained on the proper use of an external defibrillator increases the likelihood that a trained defibrillator operator is available in an emergency and thus could ultimately reduce defibrillator deployment time. Because of the importance of training defibrillator operators, the prior art has developed different approaches to defibrillator operator training. In one approach, a device generates an electrical signal that simulates either a normal or abnormal heart condition. The signal is delivered to a simulated torso or training mannequin at positions where the sensing electrodes would be properly applied to a patient. The torso also includes terminals for receiving the electrodes that provide the electrical shock. The trainee uses an actual defibrillator on the training mannequin during the training exercise in the same manner as treating a live patient. See, e.g., Spivack U.S. Pat. No. 3,453,745; Ungs et al. U.S. Pat. No. 5,275,572.
In an alternate approach, the trainee does not use an actual defibrillator. Instead, training is conducted on a separate training device which may look like an automatic or semi-automatic defibrillator and simulates the operation of a defibrillator. See, e.g., the Laerdal 911 Trainer. This second type of training device cannot actually be used to deliver a defibrillation shock to a patient. Medical organizations following this defibrillator training approach must therefore have two sets of instruments, one for training and one for actual use. This results in a significant increase in cost.
Yet another approach is the use of a defibrillator having training mode as well as a treatment mode. The training mode simulates the operation of a defibrillator in treatment mode, thus eliminating the need for separate training equipment. See, Cole et al. U.S. Pat. No. 5,611,815, issued Mar. 18, 1997 and Cole, U.S. application Ser. No. 08/648,776 filed May 16, 1996. The disclosures of these applications are incorporated herein by reference. Using a defibrillator with a training mode allows the trainer to use the same defibrillator that is deployed in the field for purposes of training potential users without actually charging and discharging the defibrillator.
It is often useful to train defibrillator users in proper electrode placement. Electrode pads that do make adequate electrical contact with the patient on proper sites on the patient's torso may not deliver effective electrotherapy to the patient. Many defibrillators, when in use to treat a patient, detect whether electrodes pads have been placed on the patient by measuring the impedance between the electrode pads. If the impedance is below a threshold value, then the defibrillator assumes that the electrode pads are on the patient. An impedance value above the threshold value could indicate that one or both of the electrode pads are not connected to the patient. A defibrillator training approach should somehow allow for training on correct electrode placement.
In one training device, a mannequin is provided that has two electrode placement sites provided with Hall-effect sensor arrays. Correct pad placement is determined based on the magnetic field produced by the permanent magnets located in each electrode relative to the sensors. The training defibrillator then prompts the user to relocate the pads as necessary until the correct location has been established. See Ungs et al. EP 0499744 A2. The sensor arrays raise the cost of this training mannequin, however.
The Physio-Control LifePak 100 defibrillator training device was used on a training mannequin with electrode connectors or studs to which metal wire had been attached in an X pattern across the mannequin's electrode connectors. During a training session, the trainee attached the defibrillator training device's electrodes to the mannequin's chest. The defibrillator training device measured the impedance between its electrodes. An impedance below a certain threshold value indicated that the training device's electrodes were properly on the mannequin, i.e., over the metal wire, which completed the circuit between the device's electrodes. The drawback of this approach, however, is that it required the use of a mannequin with protruding metal electrode connectors.
What is needed is a mannequin adaptor and defibrillator training method that permits defibrillator training with all mannequins.